hsmall

I have a question about that most BA of expressions, "Doors to Automatic".

Why, on an A380, is the command not "Doors to Automatic" but "Arm Doors for Departure" - which is far too American

I just wondered - also I am very sorry if (as I thought I remembered) this question has been asked and answered before. But I cannot find it.

PETER01

Here you go, it's a manufacturer thing apparently.

https://www.flyertalk.com/forum/21377886-post696.html

hsmall

Thank you!

newyorklondon

This is fascinating, thank you!

Really? That's hilarious! I'm sure I've seen a few Boadiceas guarding various BA lounges at LHR...

newyorklondon

This has got me thinking. Is there an actual need for booking reference numbers to be recycled?

I think possibly not based on two assumptions on my part:

1) I assume there are around 2.1 billion possibilities (A-Z, 0-9, six characters). The real number available must be lower, as there might be restrictions for various reasons (no rude words, some governing alpha-to-numeric ratio I don't know about).

2) I assume BA Media Centre's mention of "40 million customers per year" is a rough guide, but not of too much use in the calculation. I'm not sure if this means 'passengers', and I've no idea what the ratio of 'customer' to unique booking reference number is on account of group bookings, multi-sector bookings, and passengers who fly more than once per year (i.e. if one flies on more than once per year on two separate trips, is one technically now two customers in Media Centre parlance)?

BertieBadger

I think (and JAXBA's comments would suggest this) that the PNR is only unique within each GDS, i.e. Amadeus in the case of BA.

So I guess you would need to look at how many passengers records / bookings they deal with, not just BA numbers. And don't forget they will deal with more than just airlines.

A quick google suggests they deal with 440 million bookings each year (from here: Amadeus Facts and Figures Let's shape the future of travel)

So the codes might cycle round faster than you'd expect just from BA numbers alone.

newyorklondon

Ah! Understood.

Every four-to-five years or so, I guess?

BertieBadger

I'd be guessing as much as yourself at this point I don't have any knowledge of how the internals work - I suppose that would be the most optimistic case, but it could be less still.

For example, do they use both '1' (number) and 'I' (letter)? Likewise '0' / 'O' ?

I had a quick scan over 20 or so e-receipts mails, and I can't find any booking refs with numbers '1'/'0' in them (but there are letters 'I' and 'O'). Hardly conclusive of course, 20 samples isn't very many - but if they don't use those those digits then a back of the envelope calculation suggests the available number of combinations drop to roughly 1.5 billion (i.e. 34 to power of 6)

Does anyone know if digits 1 and 0 can appear in an Amadeus booking ref?

madfish

I recall a recent conversation with a telephone rep who stated that they don’t use digits 1 and O. It stemmed from me giving a PNR and pausing as I was trying to identify if it was 0 or O.

newyorklondon

The US government keeps US and EU PNR data for up to five years in an 'active' database. I presume that data includes the six-character GDS locator, but whether that locator is released for re-use in that time I don't know.

newyorklondon

It turns out they can't, just as @madfish suggests. There's a video from the 2016 Chaos Communication Congress on cryptography and security vulnerabilities in Amadeus/Sabre/Galileo here: www.youtube.com/watch?v=n8WVo-YLyAg.

It gets interesting at 31'45" when discussing brute-force guessing of GDS locators. For example, guessing a thousand random Sabre locators (Sabre only uses letters) coupled with the common surname "Smith" yields on average five live PNRs:

The relevant slide (17) from the presentation is copied below.

T8191

I was surprised that my recent BA booking had a PNR with all letters ... not a number to be seen, which I always thought was the case (except for a BA Holidays one a couple of years ago, which I thought might have been a different set).

Klrduks

I am a US resident and used it in France in April 2018 from my cell phone. It must forward the number somewhere.

flatlander

Letters (English letters) and numbers is simply an alphabet with 36 characters.

It makes searching the entire keyspace for a 6 character key about 7 times harder compared to an alphabet of only (English) letters.

Bellslea